Mechanical breaking of rocks, such as in drilling oil and gas wells, is associated with the need to set control signals (for load on rock breaking tool--drill bit and its rotary speed) depending on the lithologic type of the rock being drilled (hardness, abrasiveness, plasticity) and other specific conditions in which the production process occurs. Some of the factors influencing the drilling process may be considered unchanged during the run (drill bit life), others change during the run, and it should be noted that while the trend to the bit bearing wear and bit tooth wear with time is obvious, occurrence of non-uniformity and other lithologic deviations in rock is unpredictable. In practice, determination of control signals is associated with a continuous monitoring of the process and depends on the current condition of bit and rock being drilled independent of the drilling method--turbodrilling, rotary drilling or electrodrilling. It should be noted that no direct methods for monitoring the bit wear and changes in rock properties exist.